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Unformatted text preview: Due Monday, Feb 7, 2011 BME 201, Spring 2011 - HOMEWORK #3 Hodgkin-Huxley Model Problem I. Hodgkin and Huxley performed voltage-clamp experiments on the giant axon of the squid. Let us assume that during one try, transmembrane potential was changed from the holding voltage equal to V rest to V clamp = 10 mV. 1. Sketch a typical recording of the transmembrane current I m measured in this try. Show on your sketch the “early current” and the “late current.” 2. The “early current” is carried by which ions? Flowing in which direction? 3. The “late current” is carried by which ions? Flowing in which direction? 4. Hodgkin and Huxley first performed their experiment in the normal sea water; the Nernst potential for sodium was 57 mV. Later, they replaced some of the extracellular sodium by choline. At V clamp = 10 mV, this change totally abolished sodium current. Compute what fraction of sodium was replaced by choline ( RT/F = 25 mV)....
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- Spring '11
- Hodgkin, transmembrane potential, maximum potassium conductance, current-voltage relationship